feat(lighting): Phase G.2 — Setup.Lights + SetLightHook wiring

Register dat-defined LightInfos as runtime LightSources when entities
stream in. Every Setup (0x02xxxxxx) with a non-empty Lights dictionary
gets its per-part lights pulled via LightInfoLoader, which converts
the local Frame + ColorARGB + Intensity + Falloff + ConeAngle fields
into world-space LightSource records owned by the entity id.

Wire the LightingHookSink into the animation-hook router so retail's
SetLightHook animations (ignite-torch, extinguish-lamp) flip the
matching LightSource.IsLit latches. One hook may own multiple lights
(lamp-posts with two LightInfo entries) — the sink maintains an
owner-indexed map so all get toggled together.

Unregister on landblock unload: the streaming controller's
removeTerrain callback grabs the loaded landblock's entity list (new
GpuWorldState.TryGetLandblock helper) and drops every owner from the
sink before the entities disappear — otherwise walking across
landblocks accumulates stale LightSources.

9 new tests (LightingHookSink routing + LightInfoLoader conversion).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.App/Streaming/GpuWorldState.cs

@@ -65,6 +65,22 @@ public sealed class GpuWorldState
 
     public bool IsLoaded(uint landblockId) => _loaded.ContainsKey(landblockId);
 
+    /// <summary>
+    /// Try to grab the loaded record for a landblock — useful for callers
+    /// that need to enumerate entities before the landblock is dropped
+    /// (e.g. unregistering dynamic lights on a RemoveLandblock).
+    /// </summary>
+    public bool TryGetLandblock(uint landblockId, out LoadedLandblock? lb)
+    {
+        if (_loaded.TryGetValue(landblockId, out var found))
+        {
+            lb = found;
+            return true;
+        }
+        lb = null;
+        return false;
+    }
+
     /// <summary>
     /// Store the axis-aligned bounding box for a loaded landblock. Called from
     /// the render thread after the terrain mesh is built and uploaded.